Delivering bioabsorbable fasteners

ABSTRACT

An apparatus for delivering bioabsorbable fasteners comprises a housing and an actuator movable by a user to deliver one fastener at a time.

PRIORITY INFORMATION

This application is a continuation of U.S. patent application Ser. No. 13/755,540, filed Jan. 31, 2013, now U.S. Pat. No. 9,232,943.

FIELD OF THE INVENTION

The invention relates to sequentially deploying a plurality of bioabsorbable fasteners into tissue to secure two sides of an incision or cut in the skin or other tissue of a patient.

BACKGROUND OF THE INVENTION

There are many examples of surgical staplers which deliver staples one at a time. Most of these deliver traditional metal staples which rely on the strength of the staple to pierce the tissue and to hold the tissue surfaces together. Hence the typical surgical stapler engages the first staple at the front of a linear array of staples, and pushes it into the tissue while bending it over an anvil. Once the staple is bent into position, the tissue surfaces that are being held cannot un-bend the metal staple. One of the disadvantages of the metal staple is that it must have a portion that remains exposed through the skin surface in order to allow a medical professional to remove the fastener once biological healing is complete. This exposed portion is unsightly, and the puncture points where the fastener enters the skin, have a risk of infection.

To address the disadvantages of metal staples, various inventors have proposed fasteners made of bioabsorbable materials which can be placed below the surface of the skin. This subcuticular skin closure avoids punctures through the epidermis, and does not require follow-up removal of the staples. Such a fastener is described in U.S. Pat. No. 6,726,705 to Peterson et al, as a “Mechanical Method and Apparatus for Bilateral Tissue Fastening”. A product based on this patent, the INSORB® Subcuticular Skin Stapler, has been commercialized by Incisive Surgical of Plymouth, Minn. The fastener deployed by the INSORB device is significantly thicker in cross section than a metal staple to enable the plastic material to be strong enough to maintain the traditional “U” shape of a staple during the healing process. This added bulk is undesirable as it takes longer to be absorbed by the body. Also the head of the INSORB stapler must be inserted within the incision to deploy the fastener. This means that the user has poor visibility as to the placement of the fastener and that the device cannot be used on small incisions such as those employed in increasingly popular minimally invasive surgery.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a stapler apparatus, that is easily operated by a user, to aid in the insertion of one or more bioabsorbable fasteners for closing incisions, including small incisions such as ones that are less than 10 mm long. Another objective of the present invention is to provide good visibility to the operator of the site where the fastener will be inserted. Yet another objective is to provide a stapler loadable, or preloaded, with multiple fasteners stored in a magazine or cartridge, where the stapler is able to deploy the fasteners one at a time. A sufficient number of fasteners can be loaded or preloaded, or different configurations of the stapler can be provided, to close long as well as short incisions. Another objective of the present invention is to provide a locking mechanism that prevents fasteners from being accidentally discharged during shipment or handling prior to intentional use. An additional objective is to provide a stapler with a safety mechanism that prevents the needles from being exposed after the last fastener is delivered by the stapler.

The present application and invention is directed to a surgical stapling apparatus able to deploy fasteners of the type described by Danielson et. al. in US patent application publication number 2009/0206127 A1 “Tissue Fasteners and Related Insertion Devices, Mechanisms, and Methods” (hereinafter “Danielson”), which is incorporated herein by reference in its entirety. The present invention relates to a new and innovative delivery device that is not disclosed in Danielson and that can be used by an operator (such as a surgeon or other medical professional) to insert into tissue of a patient (such as a human or other mammal) the bioabsorbable fasteners disclosed in Danielson and to insert them generally in accordance with the insertion procedure/steps set forth in Danielson. Other types of bioabsorbable fasteners may also be used with and deployed by the disclosed apparatus.

The present invention relates to a mechanical apparatus for inserting needles into cannulated legs of a bioabsorbable fastener. The apparatus comprises a housing which orients and constrains other elements of the apparatus. Extending from the proximal end of the housing is an actuator that may be operated by the thumb of the user such that pressing the actuator into the housing causes a fastener, carried on needles and pushed by components operably connected to the actuator, to be deployed from the distal end of the housing. The housing further contains a magazine with a plurality of fasteners positioned on a reciprocally movable fastener support and a timing lever, which acts on the fastener support to move it and release each fastener one-by-one after the needles are inserted into the cannulated legs.

As the user continues to push the actuator, the needles and fastener exit the distal end of the housing and deliver the fastener between the two sides of a bifurcated foot over which the two sides of a patient's incision or cut have been positioned. The user has complete visibility of the fastener as it exits the housing before it enters the tissue, and thus can adjust the position of the stapler or tissue to precisely direct the fastener to the desired target. With manual control of speed and force, the user can deploy the fastener into the tissue such that the two legs of the fastener are inserted into the two sides of the incision. Upon releasing the actuator, it is returned by a spring to its starting position, thereby retracting the needles and leaving the fastener deployed beneath the surface of the tissue.

In order to reliably guide the needles into the cannulated legs of each fastener, the apparatus further comprises needle guide tubes made of cylindrical tubes which have an outside diameter similar in size to the outside diameter of the legs of the fastener. The distal ends of these needle guide tubes are slideably held by shaped features at the front of the magazine (“huggers”) which simultaneously contact and align the needle guide tubes and the legs of the fastener as the needles exit the needle guide tubes and enter the fastener legs. The huggers reduce the impact of normal manufacturing and assembly imperfections and tolerances, and allow the critical step of inserting the needles into the cannulated legs of the fasteners to be achieved reliably, and repeatedly, for each and every fastener loaded (or preloaded) into the apparatus.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention. In the following description, various embodiments of the present invention are described with reference to the following drawings, in which:

FIG. 1A shows a perspective view of the assembled apparatus of the present invention with safety lock installed;

FIG. 1B shows the apparatus of the present invention with safety lock removed and actuator depressed fully to deliver a fastener;

FIG. 2A shows components of the present invention with the left housing shell 20 removed to illustrate the components inside;

FIG. 2B shows the right housing shell of FIG. 2A with all components removed;

FIGS. 3A through 3D show the sequence of positions of selected parts of the apparatus at different steps during the deployment of a fastener;

FIG. 4 shows a partially exploded perspective view of the magazine and cap and selected components normally assembled together;

FIG. 5 shows a cross section of the magazine and cap taken along the A-A′ plane of FIG. 4 and including non-sectioned views of some internal components;

FIG. 6A shows a perspective view of the fastener support with the front-most fastener and guide tube support with needle guide tubes and timing lever positioned at the start of delivery of a fastener;

FIG. 6B shows the same perspective as FIG. 6A with the components positioned at an intermediate point in the delivery of the front-most fastener; and

FIG. 7 shows a cross section of the components of FIG. 4 taken along the B-B′ plane, positioned at the start of delivery of a fastener as shown in FIG. 6A.

DETAILED DESCRIPTION

FIG. 1A illustrates a perspective view of an apparatus 10 for inserting bioabsorbable fasteners to secure the two sides of an incision in tissue as illustrated in FIG. 1 and FIG. 2 of Danielson (US patent application publication number 2009/0206127 A1). For purposes of this description the proximal end, the end closest to the operator, is at the top of the figure and the distal end, the direction away from the operator, is at the bottom of the figure. FIG. 1A shows the apparatus as it may be presented to the user, preloaded with fasteners and secured with actuator lock 13, which serves as a safety to prevent the fasteners from being accidentally discharged during shipment or handling prior to their intentional use. Actuator lock 13 may be fabricated from a flexible plastic such as polypropylene by molding or die-cutting, for example, from sheet material approximately 0.030″ thick.

Now with reference to FIGS. 1A and 1B, the apparatus 10 comprises a left housing shell 20 and a right housing shell 30 which are assembled together to form a housing 25 which orients and constrains other elements of the apparatus. Extending from the proximal end of the housing 25 is an actuator 40 that may be operated by the thumb of the user. As illustrated in FIG. 1B, removing the actuator lock 13 and pressing the actuator thumb pad 43, causes actuator 40 to move into the housing 25. Guiding surfaces and components described below operate within the housing 25 such that a fastener 50 is delivered through the opening in the distal end of the housing 25. The fastener is carried on needles, and guided by guide tube support 73, to move along a line centered between the left foot 22 and right foot 32, over which the two sides of the tissue (see FIG. 12a of Danielson) have been positioned. As illustrated in FIG. 12b of Danielson, the two legs of fastener 50 penetrate the two sides of the cut tissue (see 68a and 68b of Danielson). After inserting the fastener 50 into the tissue, the user releases pressure on actuator thumb pad 43, and a spring returns actuator 40 to the starting position. As the needles retract, the fastener 50 remains in the tissue as illustrated in FIG. 12c of Danielson. Finally as illustrated in FIG. 12d of Danielson, the barbs of the fastener engage, and the cut surfaces (68a and 68b of Danielson) return in anatomical apposition with one another.

Now the various components of the apparatus 10 will be identified with reference to FIGS. 2A and 2B. FIG. 2A shows the components of the present invention with the left housing shell 20 removed to illustrate the components inside. FIG. 2B shows the right housing shell 30 alone, so that features that are obscured by the components in FIG. 2A, can be identified more easily. When components are symmetrical, the numbered features will be labeled with “a” for the left side and “b” for the right side, but in the text these symmetrical elements will be identified as “a,b”, even if only one component is visible in a particular drawing.

Now turning to FIG. 2A, the actuator 40 is shown in the “up” or starting position, which is maintained by actuator return spring 45. The travel of actuator 40 is guided by actuator tongues 47 a,b, which slide in actuator grooves 53 a,b (see FIG. 2B). A resilient arm extending from the actuator 40, forms trigger 55, which is constrained to move in cam track 61 (see FIG. 2B). At the distal end of the actuator 40 needles 65 a,b are rigidly fixed in place. The needles 65 a,b are, in one embodiment of the apparatus 10, made from surgical grade stainless steel and secured to actuator 40 by adhesive bonding or by being over-molded with actuator 40 by injection molding practices known in the art.

Needles 65 a,b are long and extend distally through the entire length of needle guide tubes 67 a,b. The needle guide tubes 67 a,b are rigidly attached to guide tube support 73. The travel of the guide tube support 73 is guided by guide tongues 59 a,b which slide in guide grooves 82 a,b (see FIG. 2B). The upward motion of the guide tube support 73 is limited by guide stops 85 a,b (see FIG. 2B), which block the travel by interfering with the proximal end of guide tongues 59 a,b.

The actuator 40 is able to push and pull the guide tube support 73, but does so indirectly by making contact with different surfaces at different times, as will be described below. A frictional engagement is provided by detent-protrusion 91 on guide tube support 73, which contacts a detent-receiver 93 on actuator 40. As the user continues to press on actuator thumb pad 43, the actuator moves and contact surface 105 on the actuator comes into contact with push-pull tab 107 on the guide tube support 73. This allows force to be transferred to needle guide tubes 67 a,b to push the fastener into the tissue, as will be explained with reference to FIGS. 3A-3D. Actuator 40 also has an actuator stop protrusion 120, which extends outward from the axis of the actuator in order to contact the stop surface 225 on the top of the magazine 200. This interference limits the distal motion of the actuator 40, and hence the depth that the fastener is inserted into the tissue. After the fastener has been deployed, the actuator 40 is able to pull guide-tube support 73 when the proximal end of detent receiver 93 engages the push-pull tab 107, the position illustrated in FIG. 2A. Finally actuator 40 has lock receiver notches 127 a,b, which allow actuator lock 13 (see FIG. 1A) to be inserted. When actuator lock 13 is inserted into actuator notches 127 a,b, downward motion of actuator 40 is blocked.

Continuing with reference to FIG. 2A, a timing lever 150 is shown in the “up” or starting position, which is maintained by timing lever spring 155. The timing lever 150 has a proximal portion which includes timing lever slot 159 which slidably contacts timing lever tab 175 on right housing shell 30 (see FIG. 2B) to guide and limit the travel of the timing lever 150. Also, at the proximal end of timing lever 150, there is a trigger engagement surface 180, which is the proximal facing surface of a feature that protrudes from the part in order to provide momentary contact with trigger 55 on the actuator 40. The distal portion of timing lever 150 is split into two legs 160 a and 160 b. The distal ends of legs 160 a,b have retractor contours 165 a,b respectively, which will be described in more detail with the description of the timing sequence of FIGS. 3A-3D.

Finally shown in FIG. 2A is a magazine cap 215, which assembles together with magazine 200, to form an enclosure that contains a plurality of fasteners and other components that will be described with reference to FIG. 5. In an exemplary embodiment, magazine 200 and cap 215 are fabricated by injection molding processes from a plastic material such as Nylon 66 (for example natural Zytel® 103 available from E.I. DuPont de Nemours & Co. of Wilmington, Del.). The magazine 200 is loosely held in position within housing 25 by magazine tabs 205 a,b (see FIG. 4), which extend through magazine slots 207 a,b (see FIG. 2B).

The present invention will be better understood from a description of the different actions involved in deploying a fastener. The different steps are illustrated in FIGS. 3A-3D but the description will rely also on references to FIGS. 2, 5, 6A, and 6B. In FIG. 3A, the guide tube support 73, the actuator 40, and the timing lever 150 are all in their most proximal (up) position. At this, the starting point, the needles 65 a,b are retracted such that their distal ends do not extend beyond the distal ends of the needle guide tubes 67 a,b. This position, as illustrated in FIG. 2A, places distal ends of needles 65 a,b 1 mm to 2 mm above the top of the front-most fastener 50 a. When the user first pushes the actuator 40, the frictional engagement of detent-protrusion 91 on guide tube support 73 with detent-receiver 93 on actuator 40 causes the guide tube support 73 to move downward together with the actuator 40.

FIG. 3B illustrates the position of the same components as shown in FIG. 3A after the actuator 40 and guide tube support 73 have moved 1 mm to 2 mm, and the distal ends of the needle guide tubes 67 a,b have made contact with the top of the front-most fastener 50 a. At this point the fastener is still supported by the fastener support 270, and cannot move downward. This interference causes the detent-protrusion 91 to disengage from the detent-receiver 93, so that the actuator 40 can continue moving downward, while the needle guide tubes 67 a,b temporarily remain motionless. An additional 1 mm to 2 mm of movement of actuator 40, which occurs after the position shown in FIG. 3B, allows the sharp distal end of each of the needles 65 a,b to protrude from the distal end opening of the needle guide tube 67 a,b, and begin to enter the cannulated legs of the fastener (described later with reference to FIGS. 6A and 6B).

In FIG. 3C, the actuator 40 has moved distally bringing trigger 55 into contact with the timing engagement surface 180 of the timing lever 150. This movement of actuator 40 also moves needles 65 a,b, which are mechanically fixed to the actuator 40, to fully insert the needles into the cannulated legs of the front-most fastener 50 a (see FIG. 6B). The interference between trigger 55 and timing engagement surface 180, moves timing lever 150 downward, causing the retractor contours 165 a,b of the timing legs 160 a,b to move fastener support 270 rearward. As illustrated in FIG. 3C, movement of the fastener support 270 leaves the front-most fastener 50 a without support, held only by the frictional contact with needles 65 a,b.

In FIG. 3D, the actuator 40 has been pushed further downward, and contact surface 105 has pressed against push-pull tab 107, causing the guide tube support 73 to push the front-most fastener 50 a from the magazine and deliver it to the tissue (see FIG. 12b of Danielson—US Patent application publication number 2009/0206127 A1). At the same time, cam track 61 (see FIG. 2B) has caused trigger 55 to lose contact with trigger engagement surface 180 of the timing lever. As the contact is lost timing lever 150 returns to its up position, forced by timing lever spring 155. This is the position shown in FIG. 3D. Once the timing lever 150 has returned, fastener support 270 is urged forward by fastener support spring 287 (see FIG. 5). However, the actual return of fastener support 270 to its initial forward position, is not possible until the needle guide tubes 67 a,b move up out of the way. This happens when the user releases pressure on actuator thumb pad 43, and return spring 45 pulls the actuator 40 upward. When actuator 40 moves upwards, the needles retract inside the needle guide tubes 67 a,b, and the proximal surface of detent receiver 93 engages push-pull tab 107, to pull guide tube support 73 and needle guide tubes 67 a,b upward to the starting position shown in FIG. 3A.

FIG. 4 shows the magazine 200 removed from the apparatus and dis-assembled from cap 215. The cap 215 may be secured to the body of the magazine by various means known in the art such as adhesive bonding or ultrasonically welding. In one embodiment illustrated in FIG. 4, a releasable attachment is provided by cap latches 260 a,a′,b,b′ on the magazine 200, which have a barbed shape at the end of a flexible arm. During assembly the flexible arms bend slightly to allow the cap latches 260 a,a′,b,b′ to be inserted through openings in cap 215. Once fully inserted, the flexible arms straighten to their original shape, and the cap latches 260 a,a′,b,b′ secure the cap by pressing against latch seats 263 a,a′,b,b′ respectively. At the top of cap 215 there is a timing lever spring tab 222 which registers the distal end of the timing lever spring 155 to hold it in place.

Continuing with reference to FIG. 4, at the top of the magazine 200 there is a stop surface 225 which stops the distal motion of the actuator 40 by interfering with the actuator stop protrusion 120 (see FIG. 2A). Huggers 210 a,a′,b,b′ extend from the front of the magazine 200 where they provide a sliding contact with the needle guide tubes 67 a,b (see FIG. 7). The magazine 200 also has timing leg support surfaces 230 a,b that provide surfaces along which the distal end of timing legs 160 a,b (see FIG. 6A, 6B) may slide. This allows timing lever 150 to be only loosely guided in its motion by timing lever tab 175 (see FIG. 2b ), which slides in timing lever slot 159 (see FIG. 2A). The critical reference geometry for timing lever 150 is provided by a sliding contact between timing legs 160 a,b (see FIG. 2A) and timing leg support surfaces 230 a,b.

FIG. 5 shows a cross section of the magazine 200 and cap 215 assembled together and taken along the A-A′ plane of FIG. 4. The left side of FIG. 5, referred to as the front of magazine 200, shows the guide tube support 73 and needle guide tube 67 a positioned against huggers 210 b and 210 b′. Within the magazine 200 are ten (10) fasteners 50 a through 50 j positioned on the fastener support 270. The front-most fastener 50 a is in close contact with hugger 210 b′, and therefore positioned directly in alignment with needle guide tube 67 a. Contact of the front-most fastener 50 a with the huggers is assured due to contact with the remaining fasteners 50 b-j which is urged forward by pusher 275 and pusher spring 277. In an exemplary embodiment, pusher 275 is fabricated by injection molding processes from a plastic material such as Nylon 66 (for example Zytel® 101L available from E.I. DuPont de Nemours & Co. of Wilmington, Del.) with smooth sliding surfaces facing the fastener support 270. Pusher spring 277 is a compression spring fabricated from, for example, Type-302 stainless steel. Pusher spring 277 is held in place by pusher spring tab 283, located on the pusher, and upper spring tab 285, located on the cap 215. Travel of the pusher 275 is guided by pusher tongues 280 a,b which travel in pusher grooves 250 a,b (see FIG. 4).

The exemplary embodiment of the present invention shown in FIG. 5 includes ten (10) fasteners 50 a-j, but it will be understood by those skilled in the art that simple changes in dimensions of the components can be made to accommodate a smaller or larger number of fasteners in the assembly. A number of fasteners in the range of 1 to 25 is contemplated by the present invention in order to provide a sufficient number to close both short and long incisions.

Continuing with reference to FIG. 5, after one of the fasteners 50 a-j is inserted into the tissue, the needle guide tubes move proximally to clear the way for fastener support 270 to move forward (returning to the position illustrated in this FIG. 5 and in FIG. 3A). Once needle guide tubes 67 a,b move proximally out of the way, pusher 275 is urged forward by pusher spring 277 to advance all remaining fasteners thereby bringing the next fastener (for example, 50 b) into the front-most position.

When all fasteners have been deployed, a safety mechanism is introduced that prevents the needles 65 a,b from being extended again. This is accomplished by pusher stop surface 286 which is the front-most portion of pusher 275. After the last fastener is delivered and the needle guide tubes 67 a,b move up and out of the way, pusher 275 moves forward (left in FIG. 5) urged by pusher spring 277, to position pusher stop surface 286 directly below the needle guide tubes 67 a,b. If the user presses on the actuator 40 in this condition the guide tubes are blocked from moving downward and the needles remain with the housing 25.

Continuing with reference to FIG. 5, the fasteners 50 a-j are positioned on fastener support 270 which is urged toward the front of the magazine by fastener support spring 287. Fastener support 270 may be fabricated by injection molding processes using a material such as Food Grade Natural Acrylonitrile Butadiene Styrene (“ABS”) (e.g. Lustran 433-000000 which is available from INEOS ABS Corporation of Addyston, Ohio). Fastener support spring 287 is a compression spring fabricated from, for example, Type-302 stainless steel. It is held in place by fastener support spring tab 293, located on the fastener support 270, and lower spring tab 297, located on the cap 215. Travel of the fastener support is guided by fastener support tongues 295 a,b which travel in fastener support grooves 240 a,b (see FIG. 4). As will be described below, the travel of the fastener support 270 reciprocates (left and right in FIG. 5) over a very short distance. In an alternate embodiment, the fastener support spring 287 could be replaced by a simple resilient arm. In such an embodiment, the resilient arm, having an effective spring rate of approximately 1 lb/inch, is molded as part of one of the contacting parts, the magazine 200, the fastener support 270 or the cap 215, to provide the necessary restoring force to move the fastener support 270.

FIGS. 6A and 6B show the fastener support 270 together with the front-most fastener 50 a, guide tube support 73, needle guide tubes 67 a,b and the distal portion of timing legs 160 a,b, to illustrate detailed features of these parts. The fastener 50 a is the type of fastener described by Danielson (US patent application publication number 2009/0206127 A1) and made from bioabsorbable materials. It is shown having a bridge 313 connecting two cannulated legs 317 a and 317 b each with barbs 333 a and 333 b respectively. The cannulated legs 317 a,b have openings 325 a,b that are chamfered at the top of legs 317 a,b. The chamfer provides a slightly larger diameter for openings 325 a,b to facilitate insertion of needles 65 a,b respectively. The fastener support 270 has a ridge 340 on which the bridge 313 of the fastener rests. Below the ridge 340, the cross-sectional shape of the fastener support 270 is designed to match features of the fasteners. In particular, sidebars 305 a,b run the full length of the fastener support 270 and are shaped to restrain the barbs 333 a,b of the fasteners from being easily dislodged upward. Thus the fasteners are able to slide in a linear fashion along the length of ridge 340 of the fastener support 270 arriving at the front-most position with a predictable position as illustrated.

Continuing with reference to FIG. 6A, the fastener support tongues 295 a,b are interrupted at the rear by notches 345 a,b which engage timing lever legs 160 a,b. The front-most fastener 50 a is positioned directly below the needle guide tubes 67 a,b and aligned with the needles 65 a,b (retracted within the tubes) because both are in slidable contact with the huggers 210 a,a′,b,b′ (see FIG. 5). Timing leg 160 a is shown with the distal end positioned in notch 345 a of the fastener support. The rearward edge of notch 345 a is in direct contact with retractor contour 165 a due to the urging of fastener support spring 287 (see FIG. 5).

In FIG. 6B the same components as illustrated in FIG. 6A are shown in a position previously described with reference to FIG. 3C. Downward movement “A” advances the needles 65 a,b inserting them into the cannulated legs 317 a,b of the front-most fastener 50 a. Simultaneously the downward movement “B” of timing legs 160 a,b causes retractor contours 165 a,b to press against notches 345 a,b to move the fastener support 270, as illustrated by arrow “C”, away from the front-most fastener 50 a. This action, taken immediately after the needles 65 a,b are inserted into the fastener, leaves front-most fastener 50 a without support from the fastener support 270. Without support from the fastener support 270, the front-most fastener 50 a is supported only by frictional contact with needles 65 a,b, and can be pushed by needle guide tubes 67 a,b to move distally out of the magazine 200.

Needles 65 a,b are made from surgical grade stainless steel or other similarly strong material(s) and sharpened with a conical point by means familiar to those in the art. The needle guide tubes 67 a,b are made from stainless steel and have an external surface that is similar in shape and size to the external surface of the fastener legs 317 a,b. Other material(s) can be used to make the needle guide tubes 67 a,b. In a preferred embodiment, the needle guide tubes 67 a,b and fastener legs 317 a,b are cylindrical in shape and have the same outside diameter. The needle guide tubes 67 a,b are spaced apart by a distance equal to the distance separating fastener legs 317 a and 317 b from one another. The needle guide tubes 67 a,b are rigidly fixed to the guide tube support 73 by means known in the art. In one embodiment, the guide tube support 73 is made by injection molding using a material such as Acrylonitrile Butadiene Styrene (ABS) or acrylics (for example, Cyrolite® acrylic based compounds available from Cryo Industries, Rockaway, N.J.). The needle guide tubes 67 a,b may be separately fabricated with a spacer-attachment structure to hold them parallel to each other. the needle guide tubes 67 a,b with such an attachment structure may be attached to guide tube support 73 by means know in the art such as screws, thermo-staking, or adhesive bonding. The stainless steel needle guide tubes 67 a,b may also be insert molded to be part of guide tube support 73 as a molded part.

FIG. 7 shows a cross section of the components of FIG. 4 taken along the B-B′ plane with the selected components positioned as previously illustrated in FIGS. 3A and 6A. The front-most fastener 50 a is shown positioned on fastener support 270 directly below the needle guide tubes 67 a,b. The legs 317 a and 317 b of the front-most fastener 50 a are in slidable contact with the huggers 210 a′ and 210 b′ respectively. Similarly the needle guide tubes 67 a,b are in slidable contact with huggers 210 a,a′,b,b′. The needles 65 a,b are constrained to move within the needle guide tubes 67 a,b which causes them to be axially aligned with openings 325 a,b. By the sequence described with reference to FIGS. 3A-3D, the needle guide tubes 67 a,b move downward to contact the top of legs 317 a,b and then the needles 65 a,b advance from within the needle guide tubes to enter openings 325 a,b.

FIG. 7. illustrates the most demanding functionality of the present invention; that is, introducing the distal points of needles 65 a,b into the openings 325 a,b at the top of the fastener legs 317 a,b respectively. This is accomplished without impossibly tight manufacturing processes by registering the critical parts and placing them into sliding contact with one another. This contact is created by the features on the magazine 200 called huggers 210 a,a′,b,b′. By adapting the needle guide tubes 67 a,b and fastener legs 317 a,b to have the same shape (e.g. cylindrical) and to have the same cross-sectional dimensions (e.g. outside diameter), both parts can be urged into contact with a common surface. In one embodiment, illustrated in FIG. 7, huggers 210 a,a′,b,b′ are in sliding contact with needle guide tubes 67 a,b and front-most fastener 50 a, which places the needles 65 a,b in axial alignment with the openings 325 a,b. Because the magazine 200 is free to move within the magazine slots 207 a,b (see FIG. 2B) it is able to remain referenced to the needle guide tubes 67 a,b due to the sliding contact of the huggers 210 a,a′,b,b′.

The apparatus of the present invention has been described with reference to ten (10) bioabsorbable fasteners of the type described by Danielson (US patent application publication number 2009/0206127 A1). Those skilled in the art will realize that the benefits of the invention may be applied to other fasteners, whether made from bioabsorbable materials or not. Realizing that the objective is to deliver fasteners one at a time from a cartridge having a multiplicity of fasteners, it will be apparent that the apparatus may be adapted by obvious modifications to deliver fasteners in greater or lesser number than ten. Alternate embodiments also can work with fasteners having a greater or lesser number of legs than two. Fasteners that do not have cannulated legs can benefit from the present invention if such fasteners are adapted to have features such as holes or slots into which guiding elements, for example needles, may be inserted. While the present invention has been set forth in terms of a specific embodiment or embodiments, it will be understood that the present invention herein disclosed may be modified or altered to other configurations. Accordingly, the invention is not limited only to disclosed details. 

The invention claimed is:
 1. Apparatus for delivering bioabsorbable fasteners that each includes a first leg and a second leg, the apparatus comprising: a housing configured to be held by a hand of a user, the housing having a proximal end, a distal end, and a length; an actuator extending out of the proximal end of the housing and configured to be moved by the user along the length of the housing and at least partially into the housing; a pair of needles operably connected to the actuator; an alignment surface configured to axially align at least one of the needles with at least one of the first and second legs of the fastener; a magazine comprising a plurality of the fasteners and a pusher configured to urge one of the plurality of fasteners at a time into contact with the alignment surface; needle guides configured to slideably guide the needles when the actuator is moved by the user to allow the needles to engage the first and second legs of the fastener, the needles and the engaged fastener exiting the distal end of the housing when the user moves the actuator; and a fastener support configured to move as a result of the actuator being moved by the user, movement of the fastener support releasing from the magazine the one fastener that is engaged with the needles and in contact with the alignment surface.
 2. The apparatus of claim 1 further comprising a locking mechanism that prevents the fastener from exiting the distal end of the housing prior to user manipulation of the locking mechanism.
 3. The apparatus of claim 1 further comprising a safety mechanism that prevents the needles from being exposed out of the distal end of the housing after all of the plurality of the fasteners have exited the distal end of the housing.
 4. The apparatus of claim 1 further comprising a spring operatively connected to the actuator and configured to be deformed when the user moves the actuator at least partially into the housing and to provide restoring force to return the actuator to a starting position when the user releases pressure on the actuator. 